Mitsubishi Electric Develops Electric Power Management System for Self-sustained Operation in Communities

TOKYO, February 14, 2013 - Mitsubishi Electric Corporation (TOKYO: 6503) announced today that it has developed a prototype electric power management system that combines an ideal mix of storage batteries and photovoltaic power generation for self-sustained operation in communities during extended blackouts. The technology was achieved through the company's Smart Grid and Smart Community initiative.

Until now, self-sufficient power management at the community level has been impossible due to difficulties in securing safe power distribution and switching over from the power-supply systems of power utilities. In light of increasing demand for power and needs for more flexible power systems to mitigate extended blackouts caused by natural disasters such as earthquakes and typhoons, Mitsubishi Electric has developed this technology to enable self-sufficient power management based on the coordination of systems operated by communities and electric power companies, thereby maximizing the use of existing power distribution networks. The technology can reduce the impact of power outages, improve the reliability of power supply and help communities to realize more safe and secure living environments.
Key technologies

1)

Ensuring safe, self-sufficient operations during blackouts

Distribution lines and substation facilities in communities are normally managed by electric power companies, so communities that are shifting to self-sufficient power management must cooperate with the electric power companies. When switching from a conventional to self-sufficient network, the safe transfer of energy to a community is determined by the electric power company.

2)

Automatic transition to self-sufficient power within 20 minutes

Communities can begin using self-contained electricity after kick-starting storage batteries, gradually raising the voltage of their electrical networks to a pre-determined level and stabilizing frequency to 50/60Hz. The time required for stabilizing voltage and frequency varies depending on the scale of the system, but automatic transition to self-sufficient energy generally is possible in less than 20 minutes following a blackout.

3)

Controlling supply and demand to avoid power shortage

When communities engage in self-sufficient power supply, the power is supplied to consumers via both storage batteries and photovoltaic generation. Surplus power generated by photovoltaic systems is used to charge the storage batteries. The system automatically adjusts power usage by suppressing photovoltaic generation and shutting down nonessential equipment to prevent the overcharging of storage batteries. Self-sufficient operations can be maintained for more than one week.